Hydraulically operated drilling platform



P 1 1958 1 R. E. FULILER EI'AL 2,852,111

' HYDRAULICALLY OPERATED DRILLING PLATFORM Filed Sept. 13, 1955 5 Sheets-Sheet 1 Arron/vi) Sept. 16, 1958 R. E. FULLER EI'AL 2,852,111

- -HYDRAULICALLY OPERATED DRILLING PLATFORM Filed Sept. 13, 1955 5 Sheets-Shee z [an/yer f. Meade/Jan} IN V EN TORS ATTOR/V')" Sept. 16, 1958 -R. E. FULLER ETA L HYDRAULICALLY OPERATED DRILLING PLATFORM Filed Sept. 15, 1955 5 Sheets-Sheet 3' Sept. 16, 1958 R. E. FULLER El'AL HYDRAULICALLY OPERATED DRILLING PLATFORM Filed Sept. 13, 1955 5 Sheets-Sheet 4 99/ f Fu//e/ O'Wy/ f. Heads/Jon 'INVENTORJ' By w. 62 9 mg ATTOR/Vir R. E. FULLER ETAL 2,852,111 HYDRAULI-CALLY OPERATED DRILLING PLATFORM Filed Sept. 15, 1955 Sept. 16, 1958 5 Sheets-Sheet 5 United States Patent HYDRAULICALLY OPERATED DRILLING PLATFORM Roger E. Fuller and Lawyer E. Henderson, Houston, Tex. Application September 13, 1955, Serial No. 534,055

9 Claims. (Cl. 189-11) This invention relates to a hydraulically operated platform with drilling rig and to such a platform having platform floor support or frame members guidably extending downwardly between skid mounted guiding support frame members on outer and inner sides thereof, the four corners of the platform floor being adjustably elevated by hydraulically operated means bearing thereagainst, and means being provided at a plurality of elevations to transfer platform support from the hydraulically operated means to the guiding support members.

It is therefore an object of this invention to provide a hydraulically operated platform with drilling rig, the supports of the platform floor therefor guidedly extending between skid mounted support members.

It is a further object of this invention to provide with such a hydraulically operated platform with drilling rig, a means at a plurality of vertical elevations to transfer support from the hydraulically operated platform elevating means to the guiding support members. i

It is yet a further object of this invention to provide in a construction of this class a means for insuring the descent of the platform floor and supports therefor by attaching the elevating piston rods of the hydraulic corner cylinders to the floor assembly.

It is yet another object of this invention to provide a skid mounted hydraulically operated platform with the skids therefor being extended to support the assembled drilling rig, including mast or derrick and drawworks, while the platform supports above the skids the rotary table of the rig.

It is another and primary object of this invention to provide a skid mounted, hydraulically lifted platform transportable in lowered position at a height to permit passage .under underpasses, bridges, and the like.

It is also an object of this invention to provide a hydraulically operated platform mounted on a skid construction of this class wherein the skids are equipped with a pivoted ramp section, folded upwardly to be supported horizontally on the skids in transit, and folded downwardly on location to first provide a graded approach for the wheeled vehicle, as a trailer, which has supported the derrick and drawworks in transit, and then to provide at location the outer support of the drawworks.

It is still a further object of this invention to provide with such a platform and drilling rig, a universally shiftable piston rod head contact by platform floor assembly at each corner thereof, such head being connected to the platform floor assembly to insure that the platform floor is drawn downwardly as the piston rod descends.

It is yet a further object of this invention to provide with such a platform and drilling rig, a manually operable hydraulic jack to supply fluid to each cylinder of the hydraulic platform elevating system whereby equal platform floor corner lifting may be obtained.

It is also a further object of this invention to provide with such a hydraulically operated platform with drilling rig a closed fluid system employing the skid construction the platform floor support and skid mounted guide supports so arranged that the central part of'the supported platform floor may be transversely braced from outer side to outer side.

Other and further objects will be apparent when the specification is considered in connection with the drawings in which:

Fig. l is a side elevational view of a drilling rig and of a platform constructed after the manner of this invention, the platform being in lowered position and the rig not having been raised;

Fig. 2 is a side elevational view of a drilling rig and of a platform constructed after the manner of this invention, the platform being in the raised position and the rig also being raised;

Fig. 3 is an end elevation taken along line 3-3 of Fig. 1;

Fig. 4 is an end elevation taken along line 44 of Fig. 2;

Fig. 5 is a sectional elevation taken along line S-5 of Fig. 2;

Fig. 6 is a perspective view of structure shown in Fig. 5;

Fig. 7 is a diagrammatic view of the hydraulic system which lifts and lowers the platform floor;

Fig. 8 is an enlarged fragmentary view, partially diagrammatic of a corner of the platform structure showing the typical corner installation of the hydraulic cylinders and pistons, as viewed along lines 8-8 of Fig. 1; to be described hereinbelow.

Fig. 9 is a fragmentary diagrammatic view of the lower part of a cylinder and the pump-jack therefor;

Fig. 10 is an enlarged fragmentary view of a piston rod connection to a platform floor assembly;

Fig. 11 is an enlarged fragmentary view of an optional form of piston rod connection to a platform floor assembly;

Fig. 12 is a plan view, partially diagrammatic, showing the arrangement of platform supports and braces, and skid mounted supports therefor; and

Fig. 13 is an elevation, part in section, the view below the floor assembly being taken along lines 1313 of Fig. l2 and of Fig. 2.

Referring to the drawings, Figs. 1 and 12 disclose the overall assembly of structures including generally parallel extending skids 15 which support thereabove a runway section 16 and adjacent thereto a floored base section 17, the runway strips being tied together with suitable transverse members 17. A ramp 18, tied together with suitable transverse members 18 is pivotally connected to the runway section 16 at 19 and releasably connected to the skids 15 at 20. In transit to location the ramp 18 has been released at 20 and pivoted upwardly so that its upper surface rests horizontally on top, of the base section 16.

After arriving at location, the ramp 18 has been pivoted downwardly as shown in Fig. l and releasably connected to the skids 15 at 20, and a wheeled trailer 21 has been maneuvered up the ramp 18 by its prime mover, and further maneuvered until the rearward of its wheels abut the base section 17 as indicated. Connection is then made between a derrick support structure 23 carried by a frame 24 upstanding from the trailer 21 and the base section 17, as by the members 25, 26, and the cross-brace 27 then ties the derrick support structure to the frame 24. Supported on the trailer 21 is the operative mechanism of the drilling rig generally designated by the numeral 28 including drawworks, engines, and auxiliary apparatus,

the unit 29 thereof serving to support one end of ader- Patented Sept. 16, 1958 J rick 30, whereas such derrick is supported centrally by a p ston rod 31 which is pivotally connected thereto and which extends to a piston within a cylinder 32 which is pivotally mounted at 33 on the trailer 21. A fluid reservoir 34 is also supported on the trailer 21 and a pump 35 draws fluid therefrom via'the :line 36 and delivers it via the line 37 to the cylinder 32below the piston to force the piston upwardly to raise the derrick 36 to the position shown in Fig. 2, in which it is latched to the support structure 23.

The end of the skids 15 opposite the ramp connected end have upright thereon spaced apart risers 38, as I-beams, across the tops of which there is connected on each side a cap beam 3. Cross-braces 4t} brace the central risers 38 and a transverse cross-brace 41 as seen in Fig. 12 ties the cap beams 39 together adjacent the base 17.

On each skid 15, inwardly of the outer frame comprising the members 38, 39, 40, and extending downwardly from the floor assembly 42, are support I-beams 43, 43 which form connection to a horizontal guide runner beam 44 as best shown in Fig. 1. On each skid still inwardly of the support means assembly 43, 43', 44 for the floor are guiding support members comprising I-beams 45, 45, upstanding from the skid 15 which beams are cross-connected by a cap beam 46 thereacross. It should be noticed that there is an interruption of these inner guiding supports 45, 45', 46, so that on each skid there is a spaced longitudinal distance between such supports for a purpose to be hereinafter described.

Referring to Figs. 8 and 12 there is shown a cylinder 47, supported by the skid 15 and upstanding thereabove between the uprights 38 and 45. A piston 48 operates in the cylinder and the rod 49 thereof extends through the upper closed end as best seen in Fig. 10 and the top of such rod is turned down to provide a shoulder 50 to support the floor beam 51. The floor beams 51 support the floor assembly 42 and are included thereby, and as has been hereinabove described, the vertical beams 43, 43 extend downwardly from the floor assembly 42 for connection to the guide runner beams 44. Above the shoulder 50 the turned down head 52 of the piston rod extends through the flange of beam 51 and a plate 53 thereabove and is secured by a nut 54 '(see Fig. 10).

With such cylinder-piston arrangement installed under each corner of the floor assembly 42 it is possible to raise the floor assembly by introducing a lifting fluid into the bottom of each cylinder below the pistons .48. As the lifting process is carried out the floor assembly 42 is lifted to raised position, so as to position the runner beams 44 at a pre-determined distance above pads 55 welded to the outer uprights 38 and inner uprights 45, 45', as best seen in Figs. 5 and 6.

Then bolts 56 are inserted through side plates or cars 57 welded sidewardly :on the upright beams, and having holes 58 therein oversize in tolerance with respect to the bolt diameters and so located with relation to the top of the pad 55 adjacent thereto that the bottom surface of the hole is at least as low as the top surface of the pad 55. Thus a nut 59 on the threaded end of the bolt 56 which extends outwardly can be tightened to thereby exert force to draw the uprights 38 and 45' together. However, before this is done to great degree the fluid pressure against the lower surfaces of the pistons in the cylinder may be relieved, thereby allowing the runner beams 44 to settle on the bolts 56 to be supported thereby, and thus the load of the floor assembly 42 is transferred from the hydraulically operated piston-cylinder arrangement to the structural supports therefor.

The fluid system for operating the cylinders is shown diagrammatically in Fig. 7. In such system the cylinders 47 are mounted on the skids 15 and a fluid inlet 60 having a valve 61 therein is connected to feed fluid into the cylinder below the piston 48 therein. Such inlets 60 connect to headers 62 which combine in a feed line 63 4 which is connected to the discharge side of a pump 64 which is mounted at some convenient out of-the-way place in the platform assembly or in the base section 17. The suction side of the pump 64 is connected by a line 65 to a reservoir 66 which may be formed by boxing in a skid 15 with steel plate on both sides, at the platform end, and across a central section to totally enclose the space between the central section and closed end. Access of fluid from .one side to another is bad by cutting an opening 67 in the web of the skid 15.

in operation after each piston 48 lifts its corner of the floor assembly 42 as the pump 64 pumps fluid into its' cylinder therebelow, the valves 61 may be closed to thereby take the load off of the hydraulic system and then the pump 64 may be shut down. Then, when it is desired to lower the floor assembly the valves 61 are opened and gravity will force the pistons downwardly in the cylinders and the fluid therefrom may return via the lines 60, headers 62, and line 63 and flow through the stopped pump 64 to the reservoir 66. Optionally valves 68 and 69 in the pump discharge and suction, respectively, may be closed and valves 76, and 71 in by-pass line 72 may be opened, and the fluid may flow through the by-pass 72 to the return line 65 and thence to the header 66.

in case it may be desired to give minor adjustment to any one corner of the floor assembly 42, as in instances where the lifted load may be too heavy over one corner as compared with the load carried by the other corners, so that one corner does not rise as high as the others upon lifting, individual jack pumps 73 are provided at each corner and suitably mounted on the skids 15. See Figs. 8 and 9. The heads 74 :of such pumps are suitably pivotally connected to any structural part of the stationary portion of the platform assembly. A valved line 78 connects the suction side of the jack pump to the reservoir 66 and another valved line 79 connects the discharge side of the jack pump to the lower end of the cylinder 47. Then, as the handle 71 is lifted fluid is drawn from the reservoir 66 into the jack pump 73 and on the downstroke it is discharged through the line 79 to the cylinder 47, the internal parts of the jack pump being conventional structures for this purpose. In this manner fluid may be supplied to any one cylinder by supply strokes delivering increments :of fluid to permit fine adjustment of elevation.

To lower the floor assembly 42 the valves 61 are opened and the load of the pistons above may be ample for them to descend under gravity and force the fluid back into the rcservoir 66, either through the pump 64 with the valves and 71 closed, the valves 68 and 69 open and the pump stopped, or through the by-pass line 72 with the valves 70 and 71 open and the valves 68 and 69 closed.

To insure that the floor assembly 42 descends with the pistons 48, the connection between piston rod 49 and flange of the floor beam 51 is made as described hereinabove (see Fig. 10), so that the descent of the pistons and the piston rods extending thereabove draws downwardly on the floor beam and thus overcomes any binding friction between the floor assembly and the outer and inner guiding supports.

In order to provide .for adjustment for the inequality of load dispersement carried by the floor assembly, the connection between piston rod 49 and the flange of the floor beam 51 may be made as indicated in Fig. 11 in which a pad 80 is welded to the lower face of the flange of the beam 51 and a concave or dished groove 81 is made therein to receive a mating head 82 of a shape to fit and turn universally within the groove 81. A bore 83 extends through the plate or pad 80 and the flange of the beam 51, and the beam 51 has at the upper end of the bore 83 a socket or groove 84 to receive the convex lower face 85 of a specially shapedbolt 86, such bolt having a shank 87 of lesser diameter than the bore 33, and the threaded end of such shank being threaded into the head 82 of the piston rod 49. Thus in case of an uneven load distribution the corner supporting the excessive heavier load may shift universally.

In order that the floor assembly 42 may have ample strength to support the loads imposed thereon it is necessary to cross-brace this assembly centrally by braces 88 which extend diagonally from the upright 43 of one runner 44 to the aligned upright 43 on the opposite runner 44 (see Figs. 1, 2, 12, and 13). Also, as best seen in Fig. 2, the adjacent uprights 43 of each runner 44 have cross-braces 89 therebetween with the result that the central part of the fioor assembly 42 is braced in box fashion thereby insuring strength in ample degree to permit each end of the floor assembly 42 to cantilever from such central supporting and guiding structure without danger of springing or collapsing.

-In order to arrive at a centrally supported and boxed, cross-braced, supported floor assembly it becomes necessary to interrupt the inner guiding supports 46 as best seen in Fig. 12, so that they do not extend continuously along the skid but are discontinued between the upright support beams 45. Thus, when the floor assembly 42 is supported on the bolts 56, additional cross-tying support is obtained between the cap beams 46 and 39 by bolts 90 which extend through holes in the Webs of the cap beams 39, 46 and are tightened by suitable nuts as shown in Fig. 5.

The floor assembly 42 includes a fioor 91 which extends over the outer and central fioor assembly and which has therebelow the transverse beams 51 and two longitudinally extending beams 93 are tied thereinto to support the rotary table 94 of the drilling rig. Outwardly of the beams 93 openings 93' are provided for access below, and the rest of the platform level is floored as best seen in Fig, 12. To provide additional floor space aprons 95 are pivotally connected at 95 to the longitudinal edges of the floor 91, see Fig. 4, and suitable uprights 96 are installed on the aprons, and also on the floor 91 in transverse direction, and such uprights have chains or guard lines 97 installed thereon to complete a protecting enclosure.

As a feature of construction when the bolts 56 have been located as shown in Fig. 5, a locater pad 97 is welded on to the bottom flange of the runner beam 44 on the opposite side of the bolt 56 from the beams 38, 45', to locate the floor assembly 42 with relation to the outer and inner guiding support assemblies, and to stop the floor assembly 42 against longitudinal displacement.

As best seen in Figs. 1, 2, and 4, a triangular frame 98 is pivotally mounted to the beams 38 on each side of the platform, and when such frames are pivoted outwardly a jack 99 supported thereby is lowered to rest upon the ground at the level of the skid base to thereby support the ring, such jack being of conventional design. Above the jack there is supported apulley 100 to serve to receive guy lines and other utility lines for use on the A closure or end gate 101 is provided to close the end of the rig opposite the ramp end, and such gate or closure is connected between the inner guiding support upright beams 45 as best seen in Figs. 3 and 4. *Outwardly of the uprights 43 the floor assembly 42 is cross-braced transversely by diagonally extending members 102 tied to the uprights 43'; and longitudinally extending crossbrace members 103 tie together the uprights 43, 43' in cross-braced relation.

The platform assembly is so constructed with relation to the derrick 31 that with the derrick raised as shown in Fig. 2, a line through the crown block sheave at the top of the derrick, not shown, extends centrally through the center of the rotary table 94.

The inter-telescoping of the floor assembly 42 with the inner and outer guiding support structures, and the arrangement whereby the ensemble of structures is braced against stresses, results in the provision of a rig which can withstand any distorting stresses and strains to which subjected, either in raised or lowered position. Additionally the provision of a hydraulic system for raising the corners of the floor assembly facilitates positioning the floor assembly at desired elevations, and the provision whereby individual corners may be lifted, either by the pumped fluid system, or by the manually operated jack pumps, insures that a line degree of lifting control is obtainable for individual corner adjustment.

Broadly this invention includes a hydraulically operated platform with drilling rig of the type having intertelescoping frame members and adapted to transfer load from hydraulic system to the skid mounted guiding supports .at a plurality of spaced apart elevations, and the invention is not limited to the structures and apparatus disclosed but other structure and apparatus is included as may fall within the broad spirit of the invention and within the broad scope of interpretation claimed and merited for the appended claims.

What is claimed is:

1. In a portable drilling rig the combination of a platform, parallel, longitudinally extending skid members having a ramp section pivotally connected in end to end relation to said skid members and downwardly pivotal to supply an inclined approach to said skids, a derrick including a derrick base supporting section carried by said skids and spaced from said ramp, a drawworks, a draw- Works and derrick supporting means adaptable for rolling lodgment upon said skid members and connected at one end to said base supporting section and at the other end to be supported by said ramp, said platform comprising inner and outer guiding support members mounted to upstand from said skids, a rotary table and a rotary table supporting platform floor therefor thereabove having platform support means connected thereto to extend therebelow in telescoping guided relation between said guiding support members, hydraulically operable means connected to each platform support means end and thereby spaced beneath the corners of said floor to lift and lower said floor and said platform support means, means at a plurality of elevations to latch said inner and outer support members together and to transfer the load of said floor and said support means from said hydraulically operable means to said support members and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

2. A drilling rig and a support therefor comprising spaced apart, parallel extending skids, a derrick and drawworks supported on one part thereof, outer guiding support members extending along the other part of said skids, inner guiding support members spaced transversely on said skids from said outer guiding support members and spaced apart longitudinally, means cross-connecting the outer ends of said outer guiding support members, gate means cross-connecting the ends of said inner guiding support members at the end of said skids opposite said rig supporting part, a rotary table and a rotary table supporting platform floor therefor above said inner and outer guiding support members, a support means connected to said platform floor to extend therebelow between said inner and outer guiding support members, hydraulically operable means connected to each cornerof said floor to lift said floor and said support means, means at a plurality of elevations to latch said inner and outer support members together and to support the load of said floor and said support means together, the lifting force of said hydraulically operable means being relieved and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

3. A drilling rig and a support therefor comprising port members extending along the other part of said skids,"

inner guiding support members spaced transversely on said skids from said outer guiding support members and spaced apart longitudinally, means cross-connecting the outer "guiding support members, gate means cross-connecting the ends of the inner guiding support members at the end of said skids opposite said rig supporting part, a rotary table and a rotary table supporting platform floor therefor above said inner and outer guiding support members, support means connected to said platform floor to extend therebelow between said inner and outer guiding support members and including horizontally extending runner members, hydraulically operable means connected to each end of said base members and thereby spaced beneath the corners of said floor to lift and lower said floor and said support means, means at a plurality of elevations to latch said inner and outer support members together and to transfer the load of said door and said support means from said hydraulically operable means to said support members by contact with said runner members and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

4. A drilling rig and a support therefor comprising spaced apart, parallel extending skids, a derrick and drawworkssupported on one part thereof, outer guiding support members extending along the other part of said skids, inner guiding support members spaced transversely on said skids from said outer guiding support members and spaced apart longitudinally, a rotary table and a rotary table supporting platform floor therefor above said inner and outer guiding support members, support means connected to said platform to extend herebelow between said inner and outer guiding support members, means cross-bracing between said support means on one side and said support means on the other side and extending across the interstitial space between said inner guiding support members, hydraulically operable means connected to each corner of said floor to lift said floor and said support means, means at a plurality of elevations to latch said inner and outer support members together and to support the load of said floor and said support means together, the lifting force of said hydraulically operable means being relieved and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

5. A drilling rig and a support therefor comprising spaced apart, parallelextending skids, a derrick and drawworks supported on one part thereof, outer guiding support members extending along the other part of said skids, inner guiding support members spaced transversely support members at the end of said skids oppositesaid rig supporting part, a rotary table and a rotary table supporting platform floor therefor above said inner and outer guiding support members, support means connected to said platform to extend therebelow between said inner and outer guiding support members, means cross-bracing between said support means on one side and said support means on the other side and extending across the interstitial space between said inner guiding support members, hydraulically operable means connected to each corner of said floor to lift said floor and said support means, means at a plurality of elevations to latch said inner and outer support members together and to support the load of said floor and said support means together, the lifting force of said hydraulically operable means being relieved and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

6. A drilling rig and a support therefor comprising spaced apart, parallel extending skids, a derrick and drawworks supported on one part thereof, outer guiding support. members extending along the other part of said skids, inner guiding support members spaced transversely on said skids from said outer guiding support members and spaced apart longitudinally, a rotary table and a rotary table supporting platform floor therefor above said inner and outer guiding support members, support means connected to said platform to extend therebelow between said inner and outer guiding support members, means cross-bracing between said support means on one side and said support means on the other side and extending across the interstitial space between said inner guiding support members, hydraulically operable means connected to each corner of said floor to lift said floor and said support means, means at a plurality of elevations to latch said inner and outer support members together and to support the load of said floor and said support means together, the lifting force of said hydraulically operable means being relieved, outrigger frame means pivotally mounted on said outer guiding support members adjacent the center of the longitudinal length thereof for pivotal extension transverse to said outer guiding support members and including jack means adjustable downwardly to bear firmly against the ground or base supporting said rig and platform to thereby maintain said platform in steadied balance and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

7. A drilling rig and a support therefor comprising spaced apart, parallel extending skids, a derrick and drawworks supported on one part thereof, outer guiding support members extending along the other part of said skids, inner guiding support members spaced transversely on said skids from said outer guiding support members and spaced apart longitudinally, a rotary table and a rotary table supporting platform floor therefor above said inner and outer guiding support members, support means connected to said platform to extend therebelow between said inner and outer guiding support members, meanscross-bracing between said support means on one side and said support means on the other side and extending across the interstitial space between said inner guiding support members, hydraulically operable means including power operated means and manually operable jack pump means connected to each corner of said floor to lift said floor and said support means, means at a plurality of elevations to latch said inner and outer support members together and to support the load of said floor and said support means together, the lifting force of said hydraulically operable means being relieved and hydraulically operable means to raise said derrick to a drilling position over said rotary table when said floor has been elevated.

8. A drilling rig and support therefor comprising spaced apart, parallel extending skids, a derrick and drawworks supported on one part thereof, outer guiding support means extending along the other part of said skids, inner guiding support means spaced transversely on said skids from said outer guiding support means, a rotary table, and a rotary table supporting platform floor therefor above said inner and outer guiding support means, platform support means connected to said platform to extend therebelow between said inner and outer guiding support means, hydraulically operable means connected to each corner of said floor to lift said floor and said platform support means, means to latch said inner and outer guiding support means together and to support the load of said floor and said platform support means together so that the lifting force of said hydraulically operable means may thereby be relieved, and hydraulically operable means to raise said derrick to a drilling posi tion over said rotary table when said floor has been elevated.

9. A drilling rig and support therefor comprising spaced apart, parallel extending skids, a derrick and drawworks supported on one part thereof, outer guiding support 9 means extending along the other part of said skids, inner guiding support means spaced transversely on said skids from said outer guiding support means, a rotary table, and a rotary table platform floor therefor above said inner and outer guiding support means, platform floor support means connected to said platform floor to extend therebelow between said inner and outer guiding support means, lifting means connected .to lift said platform floor and said platform floor support means together to predetermined elevation above said skids, means to 10 latch said inner and outer guiding support means together with said platform floor and said platform floor support means thus elevated, and to support said plat- 10 form floor and said platform floor support means as thus elevated, thereby relieving the load on said lifting means, and means operable to raise said derrick to a drilling position over said rotary table When said platform floor and said platform floor supporting means have been thus elevated.

References Cited in the file of this patent UNITED STATES PATENTS 2,429,010 Woolslayer et al. Oct. 14, 1947 2,576,389 Craighead et al Nov. 27, 1951 2,612,242 Munsinger Sept. 30, 1952 

